Shock absorber for an automatic firearm



Dec. 24, 1968 K. HARBRECHT SHOCK ABSORBER FOR AN AUTOMATIC FIREARM FiledOct. 5, 1966 Inventor: K21 2 Har bFfi 672i W 44% zl f yi. 60%

United States Patent SHOCK ABSORBER FOR AN AUTOMATIC FIREARM KarlHarbrecht, Eisental, near Buhl, Germany, assignor to Firma RheinmetallG.m.b.H., Dusseldorf, Germany Filed Oct. 5, 1966, Ser. No. 584,413

Claims priority, application Germany, Oct. 8, 1965,

R 41,719 1 Claim. (Cl. 89-498) ABSTRACT OF THE DISCLDSURE A shockabsorber for an automatic firearm having a cylinder containing aplurality of pellets and a push rod with a displacement piston in thepellets operative under spring action against an end wall of thecylinder and a cover plate in contact with the pellets.

The invention relates to shock absorbers for automatic firearmscomprising a displacement piston arranged on a buffer pin or a push rodand with a passage surrounding it, the piston being slidable in acylinder filled with a displacement medium in the form of pellets, asdescribed in U.S. Patent No. 3,251,270 of May 17, 196 6.

In many cases, particularly when the shock absorber is employed as abreech block buffer, it is desirable that there be a substantiallysmaller damping resistance to the return stroke of the displacementpiston (on counterrecoil of the breech block) than in the oppositedirection of movement of the piston.

According to the present invention, this is achieved by means of a coverplate guided slidably in the cylinder and forming a confining surfacefor the displacement medium, the said cover plate being supportedagainst the adjacent end wall of the cylinder by way of a spring. Inthis case, the return of the displacement piston can take place in asubstantially shorter time than is the case of the constructiondescribed in said patent referred to above, since the cover plateforming the forward confining surface for the displacement medium issupported resiliently in the direction of movement of the piston, i.e.in the direction of the front end wall of the cylinder. Because of this,moreover, the advantage is obtained that in those constructions in whicha return spring is provided for restoring the piston to its initialposition only a comparatively weak return spring is now required, thishaving an advantageous eifect in regard to the efforts made to achievesmall dimensions for the damping device.

In a preferred embodiment of the invention, the return spring isarranged between the front end wall of the cylinder and the front end ofthe buffer pin and the latter is moreover guided in the end wall of thecylinder and in the cover plate.

As a further advantageous development of the invention, in a shockabsorber having a hollow buffer pin for receiving a return spring, thedisplacement piston may be arranged at the inner end of the buffer pinand be guided with the latter on a guide tube fixed to the opposite wallof the cylinder and receiving the return spring. In this way,particularly favourable structural dimensions for the damping device andan extremely stable guiding action for the displacement piston areobtained.

Three embodiments of the invention will now be described in greaterdetail with reference to the accompanying drawings in which FIGS. 1, 2and 3 are each a longitudinal section of three embodiments.

The cylinder 1 of a breech block buffier contains a 3,417,660 PatentedDec. 24, 1968 displacement medium 2 consisting of solid, pellet-shapedbodies, for example steel pellets with a diameter of about 1 mm. Thecylinder 1 is only partly filled with the displacement medium, a coverplate 3 forming a forward confining surface for the displacement medium.The cover plate 3 is supported by a spring 4 acting against the frontend wall 5 of the cylinder. The end wall 5 is secured to the cylinder ina suitable manner; it is advantageously screwed in so that the initialtension of the spring 4 and thus the characteristic of the buffer devicecan be varied. A displacement piston 7 arranged on a push rod 6 isguided slidably in that part of the cylinder space which is filled withthe displacement medium. The displacement piston has a smaller outerdiameter than the internal diameter of the cylinder, so that there is anannularpassage for the displacement medium.

In the embodiment shown in FIG. 1, a return spring 6 is arranged betweenthe front end wall 5 and a collar 9 provided at the front end of thepush rod 6. In the embodiment shown in FIG. 2, the return spring 8 isarranged inside the hollow push rod and a guide tube 10 serving to guidethe displacement piston and fixed to the opposite Wall of the cylinder.This design permits particularly small dimensions and damping movementswhich are large in relation thereto.

While FIGS. 1 and 2 show embodiments of the invention in which a returnspring 8 is provided for returning the push rod, FIG. 3 shows aconstruction without a return spring. In this case, the push rod 6extends through both end walls of the cylinder and is guided in them. Aconstruction of this kind will be chosen in the case of damping deviceswith a forced movement of the push rod, i.e. in those constructions inwhich the push rod is coupled to a moving mass.

What is claimed is:

1. A shock absorber for an automatic firearm comprising in combination acylinder containing a displacement medium in the form of pellets, an endwall on said cylinder, a push rod extending into the cylinder, adisplacement piston arranged on the push rod, said displacement pistonbeing slidable with clearance inside said cylinder, a cover plateslidable within said cylinder, said cover plate forming a confiningsurface for said displacement medium, resilient means supporting saidcover plate against the displacement medium and provided adjacent saidend wall of said cylinder and a resilient return means for restoringsaid displacement piston to a forward end position in said cylinder,said resilient return means being arranged between said end wall of saidcylinder and the front end of said push rod, and said push rod beingguided in said end wall and in said cover plate.

References Cited UNITED STATES PATENTS 2,460,116 1/1949 Bazley 188-401 X3,105,411 10/ 1963 Browning 89-198 X 2,570,854 10/1951 Pierce 188101 X3,251,270 5/1966 Seifried 89198 X FOREIGN PATENTS 1,188,479 3/1965Germany.

BENJAMIN A. BORCHELT, Primary Examiner. S. C. BENTLEY AssistantExaminer.

U.S. Cl. X.R. 188l01

